The present invention relates to a method and apparatus for emptying and cleaning a viscous product, specifically tomato paste, from a cylindrical drum.
In the past, tomato paste has been emptied from drums by "head cutting" or removing one end of the drum and then dumping the product from that end. After product removal, the drums could not be reused. In addition, there was a problem of metal contaminants in the tomato paste. Also, head cutting is a labor intensive procedure.
In an approach to overcome some of the foregoing problems a costly system has been introduced by FranRica Manufacturing, Inc. In this system, the drum is rotated upside down and air is injected into the paste from a shaft extending into the bung hole. The manufacturer states that 50% to 90% of the paste is displaced in this manner. Then, warm water is delivered to the drum from three spray nozzles on a rotating assembly at the lower end of the drum. The manufacturer states that to clean a 55-gallon drum of tomato paste requires about 40 to 50 gallons of water.
Prior to emptying of the drum in the FranRica system, the drum head is subjected to a high vacuum and drawn into a convex shape. This is apparently necessary in that system because it is incapable of cleaning a drum with its end flat, presumably because of the difficulties in cleaning the area where the drum end meets the cylindrical side wall.
The FranRica system is subject to a number of major disadvantages. The equipment requires a large capital outlay due to the expensive vacuum system for drawing the drum head to a convex shape and to the cost of an expensive rotating spray head. In addition, a relatively high dilution of the paste with water is employed so that the final product is only suitable for relatively dilute applications and could not be used for more concentrated products such as catsup.